Either pop everything in the thermomix for 7 minutes on speed 4, 80C OR follow this traditional method, which I find very therapeutic and still do often if I have the 15 minutes spare
Heat your milk and vanilla pod that’s been cut in half and seeds scraped out into the milk, with the rest of the pod popped in too. A medium heat saucepan is perfect.
While it’s heating, whisk your yolks, chosen sweet stuff & tapioca flour together in a separate bowl that’s going to be big enough to pour the milk into as well.
When the milk is just come to simmer / froth around the edges, take it off the heat and pour a tiny bit into the egg mixture bowl, while stirring continuously, pour the rest in a steady slow stream until the whole milk / vanilla contents is incorporated – cook with a friend or your child – it makes this step easy peasy!
Immediately then pour that whole custard back into the saucepan on a low-medium heat, stirring continuously with a wooden spoon, until the mixture thickens and coats the spoon nicely. Do not let it bubble. That is too hot and it will curdle. If in doubt of it starting to curdle, take it off the heat immediately and pour into bowl. Liquidy custard is better than chunky curdled custard, trust me!
You are done. Pour back into bowl, vanilla pod and all to let those flavours deepen further, and pop in the fridge for a couple of hours or even a couple of days – if you can resist that long! Saved from stogy, highly processed, additive laden supermarket crapola custard forever more!